update: agent governance

- Added a new entry for hooks-state to .gitignore to exclude specific files from version control.
- Updated AGENTS.md with governance and compile verification sections, clarifying repository structure and build processes.
- Removed deprecated SKILL.md files related to execution system changes, host boundary reviews, logging visualization, MCP bridge changes, and others, consolidating relevant information into a new platform-change SKILL.md.

Author: trgiangv

.agents/skills/execution-system-change/SKILL.md

@@ -0,0 +1,31 @@
+---
+name: platform-change
+description: >
+  Short checklist for platform changes across execution, MCP/IPC, pytest bridge,
+  host boundaries, logging/visualization, or packaging. Use when editing
+  source/DevTools.*, host projects, or build/ packaging — not for routine compile
+  (hooks handle that). For other domains, use the matching skill under
+  `.agents/skills/`.
+---
+
+# Platform Change
+
+## Before editing
+
+1. Read the matching digest only: `docs/agents/execution-system.md`, `mcp-pytest-bridge.md`, `host-boundaries.md`, `build-matrix.md`, or module `docs/*/README.md`.
+2. Classify shared vs host-specific before moving code.
+
+## Rules
+
+- Shared `DevTools.*`: no Revit/AutoCAD API types; host adapters own threading, docs, rendering.
+- MCP/IPC/pytest bridge: keep wire contracts in sync (C# + Python client when shape changes).
+- Pytest bridge: treat discover and run as separate flows; do not “fix” stale path gaps with unrelated edits.
+- Packaging: `build/Modules/*` + `RevitDevTool.slnx` are source of truth; ILRepack stays off for 2027 hosts.
+- net48: rely on Polyfill + hook/multi-TFM compile; do not speculative-polyfill.
+
+## After editing
+
+- Let the stop-hook compile; fix reported errors.
+- Deploy only with `scripts/kill-host.ps1` + `scripts/build-host.ps1`.
+- Add a focused test when contracts/discovery/dispatch change; otherwise document host blockers.
+- Update the one doc layer future agents will read (module README **or** `docs/agents/` — not both by default).